This invention relates generally to heating, ventilating and air conditioning (HVAC) equipment and more particularly to single package HVAC equipment adapted to be mounted on the wall of a structure to condition the air in an enclosed space within the structure.
Single package wall mounted HVAC equipment is well known. Cost, serviceability, safety, and reliability are several factors that contribute to successful wall mounted HVAC units. Manufacturing cost and installation cost contribute to the overall cost of the equipment. Moreover, noise generated in the air supply from the HVAC units is limited by application and governmental regulations.
In the past, wall mounted HVAC units have been made with a preassembled cabinet which must be maintained intact during installation to prevent damage to the unit. This has necessitated supporting and positioning of the unit against the wall of the structure while at the same time attempting to insure that the air return and air supply duct flanges on the back of the cabinet align with the air return and air supply passages through the wall. Because the workmen could not see the duct flanges sufficiently while supporting the unit in position against the wall and because of the weight of the unit required auxiliary lift equipment to support the unit while it was being positioned on the wall, these prior art units were frequently installed with the duct flanges improperly aligned with the air return and supply passages through the wall. This has resulted in damaging the duct flanges so as to leave cracks at the wall/duct flange interface. These cracks allowed dust and small debris from the wall structure to enter the air passage through the unit and also allow air being forced out the air supply passage in the unit to escape. Moreover, the wall structure behind the cracks was exposed directly to the radiant heat from the electric resistance heater just inside the air supply duct flange. Since both the debris and wall structure were exposed to the high temperature from the heater, the heaters in these prior art units sometimes caused fires. Moreover, the efficiency of the unit was frequently reduced due to this air leakage through the cracks around the damaged duct flanges. Because the entire weight of these prior art units had to be supported by the auxiliary lift devices while the unit was positioned on the structure, the likelihood of injury and the cost of installation has been relatively high.
Some prior art wall mounted HVAC units have attempted to move the electric resistance heater away from close proximity to the air supply outlet so as to reduce the likelihood of fire from the heater. As a result, the air circulation blower was moved downstream of the indoor refrigerant coil and the heater was moved upstream of the air circulation blower. While the positioning of the heater reduced the likelihood of fires, the air circulation blowers discharged directly out of the air supply opening from the unit producing an unacceptably high noise level when no noise attenuation duct structure was located downstream of the air circulation blower. Moreover, when the air circulation blower was moved downstream of the indoor refrigerant coil, fresh air was typically introduced into the circulating air stream to the space being conditioned downstream of the indoor refrigerant coil also. This has resulted in making it more difficult to accurately control the temperature in the conditioned air being supplied back to the enclosed space.
Prior art single package wall mounted HVAC units have typically located the control box within the cabinet assembly so that the front service panel had to be removed while the service personnel gained access to the electrical and refrigerant check points in the control box for servicing the unit. This has made it difficult for the unit to be operated in the manner necessary for accurate servicing by the service personnel because the air passage through the unit had to be left open to the outside air. As a result it was difficult to accurately service the unit.
Prior art single package wall mounted HVAC units frequently have power disconnect devices that allow the power to be disconnected from the electrical components of the unit. However, these prior art units were constructed so that the disconnect devices did not have to disconnect power from the electrical components before the control box cover was removed. As a result, removal of the control box cover while power was still supplied the electrical components increased the danger of shock and damage to the electrical components of the unit.
These prior art single package HVAC units were typically manufactured with the back panel first attached to at least one of the side panels. In order to install the system components, it was necessary to temporarily support the other side of the various divider plates and other support structure eventually supported by the other side panel. This has not only made manufacturing tolerances difficult to maintain in order to insure proper cabinet alignment and also made access to the various components within the cabinet for electrical and refrigerant connections more difficult due to the presence of the back panel early in the manufacturing process.
Examples of prior art HVAC unit constructions are illustrated in the following prior art patents:
These and other problems and disadvantages associated with the prior art are overcome by the invention disclosed herein by providing a single package HVAC unit which can be easily mounted on the wall of the structure, which is easily serviced, inexpensive to manufacture and install, and which is safe to operate and maintain. The single package HVAC unit incorporating the invention has a first lightweight cabinet subassembly that can be mounted on the wall of a structure so that the air return and air supply duct flanges on the first cabinet subassembly can be easily visually aligned with the air return and air supply openings through the wall and a second heavier cabinet subassembly mounting all of the mechanical and electrical components of the unit that is installed on the first cabinet subassembly after it is installed on the wall. A hook means is provided that permits the second cabinet subassembly to engage the first cabinet subassembly in an initial tilted position and then pivot on the first cabinet subassembly to the final position overlying the first cabinet subassembly to facilitate alignment between the cabinet subassemblies during installation. The hook means may be at the top of the cabinet subassemblies so that the weight of the second cabinet subassembly causes it to pivot toward the final overlying position on the first cabinet subassembly. The invention further includes a blower assembly repositionable in the air circulation passage through the cabinet assembly so as to attenuate the noise transmitted to the space in the structure being conditioned yet maintain the required volumetric air supply output from the HVAC unit. The cabinet assembly is sized so that the blower assembly can discharge air into the air circulation passage downstream of the indoor refrigerant coil and out of alignment with the air supply outlet from the HVAC unit. The invention also includes a heater means repositionable within the air circulation passage through the cabinet assembly so as to maintain the desired orientation of the heater means to meet the operational design of the heater means. The invention includes a fresh air damper construction located in the vicinity of the air return opening into the HVAC unit and immediately downstream of the indoor refrigerant coil so that fresh air is induced into the air stream passing through the HVAC unit downstream of the indoor refrigerant coil. Likewise, the invention includes a safety interconnect means between the control box cover and the electrical disconnect in the control box to prevent removal of the control box cover without disconnecting the electrical controls in the HVAC unit from the power source. The invention also includes using a straight outdoor coil oriented diagonally of the outdoor chamber in the single package HVAC unit to minimize manufacturing cost and maximize air flow uniformity through the outdoor coil.
The invention is incorporated in a single package HVAC unit adapted to be mounted on a structure over the air return and air supply passages through the structure wall and condition the air for an interior space in the structure comprising conditioning means for conditioning the air for the interior space and a cabinet assembly housing said conditioning means including a first cabinet subassembly adapted to be attached to the wall of the structure with air return and air supply duct flanges projecting into the air return and air supply passages, a second cabinet subassembly adapted to be removably mounted on the first cabinet subassembly, and prepositioning means adapted to preposition the second cabinet subassembly with respect to the first cabinet subassembly and support the second cabinet subassembly on the first cabinet subassembly while the second cabinet assembly is moved from an initial tilted position into a final seated position in registration with the first cabinet subassembly. The prepositioning means may comprise first hook means mounted on the first cabinet subassembly and second hook means mounted on the second cabinet subassembly where the first and second hook means are constructed and arranged for the second hook means to engage the first hook means and support the second cabinet subassembly on the first cabinet subassembly. The first and second hook means may be constructed and arranged so that the second hook means can slide on the first hook means for a limited distance so that the second cabinet subassembly can be slipped into the final seated position in registration with the first cabinet subassembly and may be mounted at the top of the first and second cabinet subassemblies so that the weight of the HVAC unit causes the second cabinet subassembly to pivot toward the final seated position when the second hook means supports the second cabinet subassembly on the first hook means.
The invention may further include air circulation blower means for discharging air therefrom along a prescribed air discharge path and blower mounting means adapted to selectively mount the blower means in a first blower discharge position in the cabinet assembly with the air discharge path is generally axially aligned with the axis of the air supply outlet from the HVAC unit and a second blower discharge position so that the air discharge path is out of alignment with the axis of the air supply outlet to reduce the noise level transmitted out of the air supply outlet. The blower mounting means may include a blower mounting plate corresponding in size and shape to the cross-sectional size and shape of said air circulation passage through the cabinet assembly and fixedly mounting the blower means thereon with the blower intake opening on one side thereof and the blower discharge opening on the other side thereof, and blower plate mounting means for selectively mounting the blower mounting plate in the cabinet assembly within the air circulation passage in the first discharge position so that the blower plate is adjacent the air supply outlet and the discharge outlet opening on the blower means is axially aligned with the air supply outlet, and alternatively in the second position so that the blower plate is spaced away from the air supply outlet and the discharge outlet opening on the blower means is out of alignment with the air supply outlet and a plenum space is defined in the air circulation passage downstream of the blower mounting plate into which the air is discharged from the blower means to reduce the noise transmitted out of the air supply opening. The heater mounting means may selectively mount the heater means adjacent the air intake opening so that air passes into the blower air intake opening through the heater means to be selectively heated in a first orientation relative to the blower means when the blower means is located in the first blower discharge position and in a second orientation relative to the blower means when the blower means is in the second discharge position. The heater means may include a temperature responsive limit switch means located at a prescribed position within the heater means, and the heater mounting means may movably mount the heater means adjacent the air intake opening so that the temperature responsive limit switch means is positioned in the uppermost portion of the heater means relative to the horizontal when the blower means is positioned in the first discharge position and the second discharge position.
The apparatus of the invention may also include the indoor coil of the refrigeration circuit being generally vertically oriented and aligned with the air return opening in the cabinet assembly, a fresh air damper subchamber forming assembly positioned in the cabinet assembly between the inlet side of the indoor coil and the air return opening to define a fresh air damper subchamber sealed to the air return opening at one end thereof and to the indoor coil at the opposite end thereof so that air returning through the air return opening in the cabinet assembly passes through the fresh air damper subchamber to the indoor coil where the fresh air damper subchamber extends between opposite sides of the cabinet assembly and the cabinet assembly defines at least one fresh air inlet opening therethrough in communication with the fresh air damper subchamber; and, a fresh air damper assembly mounted in the fresh air damper subchamber adjacent the fresh air inlet opening for controlling the amount of outside air drawn into the fresh air damper subchamber through the fresh air inlet opening upstream of the indoor coil. The fresh air damper assembly may comprise a damper frame assembly mounted in the fresh air damper subchamber and defining a fresh air damper opening therethrough, a damper door pivotally mounted on the damper frame assembly and adapted to selectively close the fresh air opening through the damper frame assembly, and damper positioning means for selectively maintaining the damper door in a plurality of pivotal positions relative to the fresh air damper opening so as to control the amount of fresh air induced into the air from the space to be conditioned passing through the fresh air damper subchamber.
The apparatus of the invention may likewise include disconnect means mounted in an open front control box in the cabinet assembly with a base element in the control box and a connecting element that removably insertable into the base element to connect the electrical controls for the unit to a power source, a control box cover removably covering the open front of the control box, and interconnect means on the control box cover operatively engaging the disconnect means so as to prevent removal of the control box cover from the control box without removal of the connecting element from the base element of the disconnect means. The interconnect means may include an insertable body on the connecting element with a projecting flange and a disconnect cover member constructed and arranged to overlie the base element with an opening allowing the insertable body to pass therethrough but not the flange on the insertable body.
The apparatus of the invention may also include a front service panel sized to cover the front access opening in the cabinet assembly, a control box assembly along one side of the front access opening with the interior thereof sealed with respect to the air circulation passage through the cabinet assembly, and front service panel attachment means for selectively attaching the front service panel to the cabinet assembly in a first sealing position so that the front service panel closes the front access opening and the control box assembly, and in a second sealing position so that the front service panel closes the front access opening while leaving the control box assembly uncovered whereby the interior of the control box assembly is accessible from outside the cabinet assembly for service while the air circulation passage remains sealed to allow the HVAC unit to operate as designed during servicing. The control box assembly may include an open front control box defining a sealing lip thereon extending across the access opening and coplanar with the periphery of the access opening and the front panel attachment means may include a first set of holes in the front access panel, a second set of holes in the cabinet assembly in registration with the first set of holes when the access panel is in the first sealing position, a third set of holes in the cabinet assembly in registration with the first set of holes in the access panel when the access panel is in the second sealing position.
The apparatus of the invention may also include a straight outdoor coil assembly mounted in the outdoor chamber of the cabinet assembly and extending diagonally across the outdoor chamber where inlet openings through the side and bottom of the cabinet assembly supply outdoor air to one side of the coil assembly and a discharge opening in the front of the cabinet assembly provides a discharge of air from the opposite side of the coil assembly, and an outdoor air circulation means for moving the air through the outdoor coil assembly. The refrigerant compressor may be mounted in the outdoor compartment downstream of the outdoor coil assembly. The cabinet may define an outdoor chamber access opening to the front of the outdoor chamber with the outdoor air circulation means including an outdoor air fan mounting panel removably mounted on the cabinet assembly to close the front of the outdoor chamber and defining the front outdoor air discharge opening from the outdoor chamber therethrough, and an outdoor air fan assembly directly mounted on the outdoor air fan mounting panel and overlying the front outdoor air discharge opening to draw outdoor air through the outdoor coil assembly and force the outdoor air out of the outdoor air chamber through the front outdoor air discharge opening. The outdoor air circulation means may further include a spun single piece venturi member attached directly to the outdoor air fan mounting panel around the front opening to form a venturi around the outdoor air fan assembly and stiffen the outdoor air fan mounting panel.
These and other features and advantages of the invention will become more clearly understood upon consideration of the following detailed description and accompanying drawings wherein like characters of reference designate corresponding parts throughout the several views and in which: